BenchmarkofRF-Track&AstrawithPRAE
YanliangHan
LAL,France
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PRAEPlatformforResearchandApplicationwithElectrons
Beam parameters Phase A-B Energy,MeV 50-70(100-140) Charge(variable),nC 0.00005–2 Normalizedemittance,mm.mrad 3-10 RFfrequency,GHz 3.0 Repetitionrate,Hz 50 Transversesize,mm 0.5 Bunchlength,ps <10 Energyspread,% <0.2
Bunchesperpulse 1
q PhaseA:RFgunat50Hz;50-70MeV,twolines:
q Direct:magneticchicaneforProRadandradiobiologyinmode“Push-Pull”
q Deviated:forInstrumentation
q PhaseB:q SpectrometerforInstrumentationline
q Scanningdipoleforradiobiologyq Completesetofchannels
q 140MeV
RFGun Linac
ProRad
Radiobiology
Instrumentation
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The RF gun
Coupling slot compensating the Field distortion
RF power (5 MW)
Short circuit
Photocathode
Acceleratinggradient(TM010_πmode):80MV/matPin=5MW
2.5 cells RF gun designed and produced at LAL for ThomX
Operation frequency 2998,55 MHz (30°C, in vacuum)
Charge 1 nC
Laser wavelength, pulse energy 266 nm, 100 µJ
RF Gun Q and Rs 14400, 49 MΩ/m
RF Gun accelerating gradient 80 MV/m @ 5 MW
Normalized emittance (rms ) 4.4 π mm mrad
Energy spread 0.4 %
Bunch length (rms) 5 ps
Photoinjectorspecification
CST-Particle in cells, simulation results
Energy gain = 5 MeV for Pin =5 MW
20 cm
bucking coil focusing coil new coil configurations
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RFGunPhasescan
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1.5
2
2.5
3
3.5
4
4.5
5
5.5
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80 100 120 140 160 180 200 220 240 260 280 300
Ekin
(M
eV
)
phi (degree)
RF-TrackAstra
Formula simulation• Thephaserange– Astra:180:280– RF-Track:90:180
• Theenergygain– Astra:5.11MeV– RF-Track:5.28MeV
• Theparticleloss– Astra:0-70%– RF-Track:0.01%
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Phasespace-horizontal
AstraRF-Track
Usethephasewithlargestenergygain
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Phasespace-longitudinal
Totallydifferent!
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EmittancealongtheRFGun
InAstra AttheendofRFGunBz=0,thedefinitionisthesame
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ThestabilityofRF-Track
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Phasespacestability–RF-TrackTheparameter“sc_nsteps”meansapplyingspace-chargekickaftereach“sc_nsteps”integrationsteps.IntegrationalogrithmisRunge-Kutta-45.
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Phasespacestability–RF-Track
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Phasespacestability–RF-TrackNomagneticfieldforspacechargeeffect
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Phasespacestability–RF-TrackNomagneticfieldforspacechargeeffect
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Phasespacestability–RF-TrackUsingdifferentintegrationalogrithm– analytic
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Phasespacestability–RF-TrackUsingdifferentintegrationalogrithm– analytic
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Conclusion
• Thereareseveraldifferencesbetweentwocodes– Thephaserange– Theenergygain– Theparticleloss– Phasespacedistribution– Theemittancedistribution
• TheresultfromRF-Trackisstable– Withdifferentspace-chargesetup– Fordifferentintegrationalogrithm
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Advantage&Disadvantage
Advantage:• Opensource• Octave&Pythoninterface• Therearemanyalgorithmto
choose• ParallelProcessingDisadvantage:• Thereisusermanualnow.
Advantage:• Thereisausermanual.• Crossplatform-WindowsDisadvantage:• Singlethread
RF-Track Astra
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